Automatic guides for travelling bands or belts



Jan. 15, 1957 J. CRUICKSHANKS 2,777,331

AUTOMATIC GUIDES FOR TRAVELLING BANDS OR BELTS Filed Oct. 28, 1952 4Sheets-Sheet l FIG. 7

Jan. 15, 1957 u c 5 A s 2,777,331

AUTOMATIC GUIDES FOR TRAVELLING BANDS 0R BELTS Filed Oct. 28. 1952 4Sheets-Sheet 2 n- 1957 J. CRUICKSHANKS 2,777,331

AUTOMATIC GUIDES FOR TRAVELLING BANDS 0R BELTS Fi led Oct. 28, 1952 4Sheets-Sheet 5 1957 J. CRUICKSHANKS 2,777,331

AUTOMATIC cums FOR TRAVELLING BANDS 0R BELTS Filed Oct. 28, 1952 4Sheets-Sheet 4 United States Patent AUTOMATIC GUIDES FOR TRAVELLINGBANDS OR BELTS John Cruickshanks, Edinburgh, Scotland, assignor toBertrams Limited, Edinburgh, Scotland Application October 28, 1952,Serial No. 317,341

Claims priority, application Great Britain October 29, 1Q51 2 Claims.(Cl. 74-241) This invention relates to automatic guides for travellingbands or belts, such as the wire of a Fourdrinier papermaking machine towhich the present invention is particularly, but not exclusivelyapplicable.

Each such guide consists fundamentally of a guide roller, over which theband or belt is arranged to travel, means for eifecting angularadjustment of the axis of the said guide roller relative to a normalposition at right angles to the direction of movement of the band orbelt, a feeler movable by engagement of the band or belt therewith whenthe belt moves laterally out of its intended normal running position andmeans adapted to be actuated by the movement of said feeler formotivating the angular adjustment means aforesaid to correct the saidlateral movement of the belt. Such guides are hereinafter termedautomatic guides of the kind referred to.

One of the main problems with such automatic guides is the tendency forhunting, that is to say, unless they are set with a wider tolerance thanshould be necessary they operate to adjust the guide roller first in onedirection and then almost immediately in the other direction and so onbackwards and forwards causing the band or belt to be moved ceaselesslyfirst to one side and then to the other of the intended or normalrunning position.

The present invention is based upon a fuller appreciation thanheretofore not only of the cause of such hunting but of thepossibilities of correcting the same. In

the first place it is fairly obvious that hunting is caused by ade-activating time-lag, i. e. the time-lag between the adjustment of theguide roll into a new angular position and before the full effect ofsuch adjustment has been transferred to the band or belt. Consequentlythe feeler continues to motivate adjustment for some time after thecorrect adjustment of the guide roller has actually been made, that isto say after the amount of adjustment has been made which, given time,would be suflicient to correct the displacement of the band or beltwhich initiated such adjusting movement. That however is only one factorand the most obvious at that. Another and less obvious factor is theactivating time-lag, i. e. the time-lag between the moment when thefeeler is moved past a critical position and motivates the adjustingmeans and the time required by such adjusting means to provide aneffective movement of the'guide roller. All such adjusting means havenot only been slow in action, probably purposely so to try and reducethe violence or rapidity of hunting, but also they have acted at one setspeed unrelated to the urgency or otherwise of the need for adjustment,that is to say the rate of adjustment of the guide roller is the samewhether the band or belt is an inch or 6 inches off its properalignment, and this is another factor operating adversely to theefficient action of an automatic guide.

The present invention appreciates therefore that a better and moreefliciently operating automatic guide can be provided by removing one orboth of the char- ..acteristics of existing devices which give rise tothe 2,777,331 Patented Jan. 15, 1957 belt so as to provide earlierdemotivation of the adjusting means.

According to a further feature of the invention the adjusting means forthe guide roller includes means the speed of actuation of which isproportional to the lineal displacement of the feeler beyond itscritical motivating position, whereby the speed of adjustment of theguide roller is proportional to the need for adjustment.

In the accompanying drawings:

Fig. l is a part sectional side elevation showing one end of a guideroller and its control mechanism made in accordance with one example ofthe invention;

Fig. 2 is a plan of Fig. 1 showing the same end of the guide roller andits mechanism;

,Fig. 3 is a part sectional end elevation on line 3--3 of Fig. 2 showingthe same end of the guide roller;

Figs. 4, 5 and 6 are exaggerated line diagrams illustrating thefunctional movements of the control mechanism;

Fig. 7 is a part-sectional plan view similar to Fig. 2 but illustratingan alternative arrangement, and

Fig. 8 is a sectional plan view of the valve of the arrangement shown inFig. 7.

In the example of the invention shown in the drawings the wire guideroller (1 of a Fourdrinier machine is mounted in the usual manner thatis to say the bearing housing a at each end of the roller includes astem b for pivotal movement, While at one end as shown in the drawingthe bearing block c is slidably adjustable in guides c to enable theangular relation of the guide roller to the belt d to be changed.Instead of the usual adjusting means consisting of a feed screw andratchet actuating means for turning the screw, hydraulic rams e, e areprovided at each side respectively of the bearing block 0, the cylindershaving brackets f, f by which they are rigidily attached to the frame gof the machine and the pistons being attached by the piston rods h, h tothe bearing block 0. On the bearing block is mounted by means of amounting a hydraulic valve consisting of a cylindrical housing i inwhich is rotatably mounted a control vane 2' In the housing are a pairof ports 1', f in diametrically opposed relation connected by flexiblepiping k, k respectively to the outer ends of the hydraulic cylinders.Also in the housing and disposed at right angles to the two firstmentioned ports and diametrically opposite to each other are inlet andexhaust ports I, I connected to the pressure and return pipe lines of apump or other means (not shown) for providing hydraulic pressure. Thecontrol vane i of the valve is adapted to be actuated by a feelerconsisting of a palm or plate-like member n7 attached one to each end ofa rod m which is slidably mounted in guides (not shown) adjacent to theedges of the band or belt d. The palms on opposite sides of the band orbelt d are adjustably secured by bolts m? to the rod m and are setspaced apart a distance slightly greater than the width of the band orbelt so that while the belt is running reasonably true and centrallywith the guide roller a normal to the run of the belt, neither edge ofthe belt will engage its adjacent palm. The sliding rod m carrying thetwo palms is connected to one arm of a bell-crank lever n pointingrearwardly relative to the run of the belt, the other end n of whichlever extends outwardly and parallel to a lever 0 secured to the spindleof the control vane i and is connected thereto by a link p. A centeringspring 0 is provided on the valve lever. A bracket y extends outwardlyfrom the base y and is provided with an upwardly extending body portionz upon which the arms 11 and n of the bell crank lever are pivotallymounted.

In operation, as shown particularly in Figs. 4, 5 and 6, if the band orbelt d wanders to one side or the other of its normal position its edgewill engage and push the palm 121 thus immediately turning the valvevane one way. The parts are shown in Fig. 4 in their normal initial setpositions. Such movement of the belt to the dotted line position :5inclines both the arms 11 and o and moves the vane to open the port jconnected to the cylinder 0 to the pressure inlet port I and at the sametime connects the other port j to the outlet port 1 The hydraulicpressure fluid entering the left hand cylinder immediately initiatesmovement of the piston 12 causing the other piston 11 to expel fluidfrom its cylinder. The resultant movement of the bearing block 0 beingdependent on the rate of flow of the fiuid is therefore, directlydependent on the amount of movement of the vane i and therefore of thepalm m. A very rapid movement of: the bearing block c carrying the guideroller bearing housing a may therefore be provided, and as the movementimparted to the palm will necessarily be in the form of periodicimpulses due to irregularities in the run of the edge of the belt, thesensitivity of the arrangement may be so set that an almostinstantaneous adjustment movement is obtained from a high part of therun of the belt. By high part of the belt is meant any part of the edgeof the belt whichiis out of line with the remainder of the edge of thebelt, for example by reason of any deformation of the belt. Overadjustment movement is avoided partly by the sensitivity of suchhydraulic control to the high part which may release the palm by passingit before adjustment movement of the guide roller has had time to movethe belt across. In addition to this however, it is to be noted fromFig. 6 that any adjustment to the right of the guide roller bearingblock C also operates through the lever and linkage to effectre-centralizing of the valve although the palm may still remaindisplaced as if in contact with the belt shown in the chain lineposition (1 The valve vane can therefore de-motivate the hydraulic ram 0before the edge of the belt allows the palm to return to its originalposition and although the result is a permanent relative displace mentof the palms from their on'ginal position, such displacement is onlysmall and immaterial under normal conditions compared with the checkwhich it puts upon any tendency to hunt. After such adjustment of theguide roller, the belt will, in due time run away from the palm which ithad just actuated but not so far as to engage the other palm because theadjustment motivation of the guide roller has been, at least in part,checked by the closing of the valve from the combined movement of thepalm and the lateral adjustment movement of the bearing block 0. Theultimate result of this lateral adjustment of the palms is that they canbe set closer to the run of the high parts than has hitherto beenpossible because of hunting and thereby the guide is given greatersensitivity.

In Fig. 7 is illustrated an alternative arrangement in which thefunction of pistons 2 e and cylinders F, f are the reverse of thefunctions of the corresponding parts of the embodiment previouslydescribed. The pis tons e e are rigidly fixed on the machine framewhilst the cylinders f 1' (which are integral) are supported for slidingmovement in guide c and carry a hydraulic valve consisting of anellipsoidal housing 1' in which is rotatably mounted a control member i(see Fig. 8).

The valve body 1' is bolted to the walls of the cylinders f and fPassages and associated ports are provided within the valve for inletand outlet of hydraulic fluid, which is conveniently water underpressure, but may equally well be compressed air or oil under pressure.Thus, there are inlet passages f and f in the walls of the cylinders,complementary passages 1' and i in the body of the valve leading to thehousing 1' an inlet socket i also leading to the housing 1', an outletpassage 1' from the housing i and an outlet hole 1' from the lastpassage for return flow.

In operation the alternative arrangement just described is exactly thesame as the arrangement shown in Figs. 1 to 6, except that the movableelements are cylinders and the stationary elements pistons. It will beclear that one advantage of this is that flexible pipe connections areno longer necessary, which cheapens and simplifies the design.

I claim:

1. Apparatus for controlling the transverse position of a horizontaltravelling band trained on a rotating roll comprising, a support, ashiftable bearing means for journalling the rotating roll and includinga pivotable stern whereby the angular position of the axis of therotating roll is shiftable with respect to the path of the travellingband, a pair ol": guides fixed to said support at one end of therotating roll, a slidable bearing block adjustable between said guidesand supporting the stem of said shiftable bearing means, a pair ofhydraulic cylinders, each of said hydraulic cylinders secured to saidsupport at :1 side of said slidable bearing block and having a pistonreciprocable therein and provided with a piston rod fixed to saidslidable bearing block, an hydraulic valve mounted on said slidablebearing block and having iii) a control vane rotatably mounted thereinand connected to each or: said hydraulic cylinders for adjusting saidslidable bearing block. angularly relative to a normal operatingposition at right angles to the direction of movement of the travellinghand, pump means connected to said hydraulic valve for supplyinghydraulic pressure thereto, a feeler member on each side of thetravelling band and being responsive to changes in the transverseposition of the travelling band with respect to the rotating roll, abell crank lever pivotally mounted on said support, a shiftable feelerrod connecting said feeler members to said bell crank lever, and a linkconnecting said bell crank lever to the control vane of said hydraulicvalve, all adapted and arranged with the edge of the travelling bandengaging and actuating said feeler members with said feeler rod and bellcrank and link and the control of said hydraulic valve being responsivethereto and effecting actuation of said hydraulic cylinders and slidablebearing block therebetween whereby the adjusting movement of saidbearing means away from its normal position is accomplished to maintainthe travelling band in a desired transverse position on the rotatingroll.

2. The apparatus of claim 1 with the movement of the rotating roll tonormal position simultaneously effecting return actuation of said feelermembers to their original undisplaced positions.

References Cited in the file of this patent UNITED STATES PATENTS1,066,687 Warren .luly 8, 1313 2,199,893 Norton et al. May 7, 19462,291,830 Obenshain Aug. 4, 1942 2,488,294 Hornbostel .d Nov. 15, 19492,632,642 Cooper Mar. 24, 1953

